Interestingly, although humans can develop macular colobomas [30], NHEJ1 variants described in humans manifest as immunodeficiency, microcephaly, and growth delay [31,32], and the relationship between the 7.8 kb canine NHEJ1 variant and non-ocular disease states (i.e., immunodeficiencies) is unknown [23]. Here, NHEJ1 is linked to microcephaly.